Threaded Multilayer Tube Connection Without Adhesion Treatments

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Solution Overview

Problem

Existing multilayer tubes for chemical and food-related fluids are complex to connect, requiring laborious removal of outer layers and posing handling difficulties due to metallic parts, with adhesion treatments complicating the assembly process.

Innovation Solution

A multilayer tube design featuring a corrugated tubular sheath with a mechanically coupled female-threaded layer and an internally and externally threaded tubular connecting element that screws into place, eliminating the need for adhesion treatments and simplifying assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the tube uses metallic wire winding for reinforcement, then the tube gains flexibility and resistance to collapsing, but the tube becomes heavy and difficult to handle

Engineering Contradiction:
Improveresistance to collapsingVSAvoidtube weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent replaces metallic wire winding with a corrugated structure made of the same polymer material as the tube body. This changes the reinforcement parameter from metallic composition to geometric corrugation, maintaining mechanical strength while eliminating the weight penalty of metal components.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite structure where the corrugated layer is formed from the same fluoropolymer material as the smooth inner layer, creating a homogeneous composite reinforcement that provides structural strength without introducing heavier metallic materials.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If the tube requires removal of outer layers for connection, then the connection can be made, but the installation becomes laborious and requires skill

Engineering Contradiction:
Improveconnection capabilityVSAvoidinstallation complexity
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent divides the tube into distinct functional layers (smooth inner layer for fluid flow, corrugated outer layer for reinforcement) that can be independently configured. The connection mechanism is integrated into the corrugated structure itself, allowing direct connector attachment without removing protective outer layers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The corrugated structure serves dual purposes: it provides mechanical reinforcement and simultaneously creates built-in attachment points for connectors. The helical peaks and troughs of the corrugation automatically engage with connectors, eliminating the need for separate adhesion treatments or layer removal operations.

Inventive Principle:
Principle #25Self-service

3Reliability

If the tube uses adhesion treatments for layer bonding, then the outer layer adheres better, but the assembly process becomes more complex

Engineering Contradiction:
Improvelayer adhesionVSAvoidassembly process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces chemical adhesion treatments with a mechanical interlocking system. The corrugated structure's geometric features (peaks and troughs) provide physical engagement with connectors and layers, substituting chemical bonding processes with purely mechanical attachment that is simpler and more reliable.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Instead of making the outer surface adhesive through chemical treatment, the patent inverts the approach by making the inner structure (corrugation) mechanically engaging. The connection reliability comes from the mechanical interlock of the corrugated geometry rather than surface adhesion chemistry.

Inventive Principle:
Principle #13The other way round (Inversion)

4Ease of operation

If the tube has smooth inner surface, then the fluid flow is smooth, but the tube lacks flexibility compared to corrugated structure

Engineering Contradiction:
Improvefluid flowVSAvoidflexibility
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent applies different surface qualities to different parts of the tube: the inner surface remains smooth for optimal fluid flow, while the outer surface is corrugated for flexibility and reinforcement. This local differentiation allows each surface to optimize its specific function without compromising the other.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent resolves the flexibility-flow contradiction by moving the corrugation to a different dimension - the outer surface geometry - rather than the inner fluid-contact surface. The corrugation amplitude and wavelength are designed to provide flexibility while maintaining sufficient inner surface smoothness for fluid flow.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design enables rapid, reliable, and cost-effective connection of multilayer tubes with reduced complexity and weight, enhancing handling and maintenance by using mechanical threading for secure fluid passage.

Implementation Method 1

at least one second layer (12), which is shaped internally like a female thread and is coupled mechanically to the first layer (11) through the interaction of the threading

Methodology Applied
Scientific EffectMechanical threading coupling: Mechanical Fastener

Data Source

PatentEP3660379B1Connecting structure of a multilayer tube, particularly for chemical and food-related fluids
Publication Date: 2022.07.27 TUBIGOMMA DEREGIBUS
  • EP3660379B1 patent drawingFigure 1~4

AI summary

A connecting portion of a multilayer tube, particularly for chemical and food-related fluids, the multilayer tube comprising, in succession from the inside outward: - a first layer (11) constituted by a tubular sheath that is externally corrugated in a screw-like manner and which defines the duct for the fluid, - at least one second layer (12), which is shaped internally like a female thread and is coupled mechanically to the first layer through the interaction of the threading, and the connecting portion (13) being characterized in that it comprises: - a tubular element (14) which is internally and externally threaded and is inserted at a corresponding end (15) between the first layer (11) and the at least one second layer (12) via screwing.